Switching gear is installed as a power reception/distribution device in a power system to receive generated power from a power plant and distribute it to a load. A switching unit is installed in switching gear and is a key part of the switching gear which houses a switch.
Recently, in urban areas there has been a problem that power consumption concentrates in certain regions and construction of distributing substations in response to the growing demand for power consumption is difficult and there is shortage of space for installation of power distributing pipes. In addition, the demand for higher operating rates of supply facilities is growing. In order to respond to the demand, studies have been conducted on the construction of efficient power supply facilities which encourage a high voltage system to absorb loads by boosting the distribution voltage, namely increasing the capacity per line. To this end, distributing implements and substation equipment for the high voltage system must be more compact.
Also, since the inside of the switching gear is hot mainly in the current conduction area when a large current flows, the cooling performance must be improved for a large current to flow. An example of switching gear with a function to improve the cooling performance as mentioned above is described in Patent Literature 1. Patent Literature 1 describes that cooling performance is improved by providing resin or metal fins on the resin layer covering the switching gear.